WASHINGTON -- Rep. Steny H. Hoyer goes to the White House today to hear a presidential pitch for the North American Free Trade Agreement, but if President Clinton expects the Maryland Democrat to announce his support afterward, he will be disappointed.

"If the vote were held today, I'd vote against it," the chairman of the House Democratic Caucus said yesterday. But Mr. Hoyer left open the slim possibility that he would vote for the controversial deal, which would eliminate trade barriers between the United States and Mexico.

"I'm not committed to vote no and certainly not committed to vote yes -- that would be a surprise to most people," he said.

His visit to the White House comes during a week when the administration is making a strong push to promote the trade agreement in Maryland.

If Mr. Hoyer opposes the agreement, it would leave Speaker Thomas S. Foley of Washington as the only member of the House Democratic leadership in favor of NAFTA. Rep. Richard A. Gephardt of Missouri, the majority leader, and Rep. David E. Bonior of Michigan, the majority whip, have announced their opposition. Mr. Hoyer's opposition would be in tune with the majority of the Democratic Caucus, who either oppose or lean against the agreement at this point.

"Hoyer is one both sides are especially working on rather hard because of his leadership position," said William M. Daley, the Chicago banker who is spearheading the administration effort to win approval of NAFTA.

Labor unions, which have been generous with campaign contributions to the Southern Marylander, are leading opponents and have put considerable pressure on Mr. Hoyer to vote against the agreement, in some cases threatening to withhold campaign donations if he supports the agreement.

At the same time, he is being lobbied heavily by the administration. Mickey Kantor, the U.S. trade representative, has visited him, and Mr. Daley is expected to pay a visit, said a Hoyer aide.

Mr. Hoyer and Rep. Benjamin L. Cardin of Baltimore are the only Marylanders in the House who have not said how they will vote on NAFTA. Republicans Wayne T. Gilchrest and Constance A. Morella say they will vote for the agreement. Committed against it are Republicans Helen Delich Bentley and Roscoe G. Bartlett and Democrats Kweisi Mfume and Albert R. Wynn. Democratic Sens. Barbara A. Mikulski and Paul S. Sarbanes have not taken positions, though both say they have reservations about the pact.

Mr. Hoyer's concern about the agreement centers on jobs. He says there will be "substantial, short-term dislocations" that the United States is not prepared to absorb.

Proponents of the agreement argue that the deal will mean a net gain of 1,700 jobs for the state.